When it comes to assessing Colorado’s chances for replacing diesel-belching heavy trucks with cleaner electric versions anytime soon, the state’s trucking industry offers an anecdote about Tesla.
Given the erratic celebrity of CEO Elon Musk, who was made the richest person in the world by Tesla’s rise, the true story is suitably apocalyptic.
Colorado’s top trucking companies have known for years that state leaders planned to copy California law and require a growing portion of new heavy trucks to be electric beginning in 2027. They’ve fought the proposed policy. But they also hedged and began putting deposits on one of the few clean trucks on the horizon, Tesla’s much-hyped, sleek electric semi-tractors. That was 2019.
At the time, delivery was expected in 2020.
None of the Colorado companies have received a Tesla truck yet. Tesla finally started delivering a few elsewhere in February 2022.
Last week, all the electric trucks Tesla had delivered were recalled, because of brake problems.
“We’re supportive of moving to the zero-emission vehicle environment. It’s just when you start to move up in size of vehicles, the technology chunk is substantial,” said Greg Fulton, president of the key trade group Colorado Motor Carriers Association.
Emissions from the transportation sector make up a large portion of both greenhouse gases that cause climate change, and the local chemical stew that bakes into lung-damaging ozone under Colorado’s summer sun. While medium- and heavy-duty trucks are just 10% of the vehicles on U.S. roads, they put out 25% of the greenhouse gas emissions from transportation, according to the Union for Concerned Scientists.
Colorado’s Air Quality Control Commission previously adopted California’s standards for selling an increasing number of electric vehicles for the state’s light passenger vehicle fleet. More than 10% of new cars bought by Coloradans are now EVs.

Now the AQCC is turning its attention to the stubborn diesel emissions of the heavy truck sector, with testimony, a debate and a vote scheduled next week that would make Colorado among the half-dozen states to adopt California’s heavy truck requirements. The EPA earlier this year gave California the waiver it needed to make its heavy truck rules more stringent than federal standards.
State air quality officials and environmental groups say the so-called Advanced Clean Trucks vote is another crucial step in Colorado’s efforts to meet both climate emissions goals and EPA ozone caps, which the northern Front Range has violated for years. They also see it as a big down payment for the environmental justice movement, bringing cleaner vehicles to the lower-income neighborhoods that have long choked on diesel emissions from surrounding interstates and the trucking businesses based there.
Community events on the clean trucks policy have been overwhelmed by Spanish-speaking residents enthusiastic about both a less-polluting trucking industry around them, and the chance to buy new or used electric passenger cars, said Juan Madrid, clean transportation and energy advocate for Colorado GreenLatinos. An Aurora event ran out of translation headsets, he said.

“Black, brown, and Indigenous communities are all interested in this technology not just for the health benefits, but on how this will help improve their lives. And then some of those folks were asking about electric heat pumps and asking about building electrification and solar,” Madrid said. “The technology is there, and often the administration and legislators don’t think that this population is interested or can afford this technology. But they are interested.”
Under the clean trucks law passed by California and now being matched by other states, zero-emissions vehicles must make up between 40% to 75% of new sales by 2035, with the amounts varying by weight category. If Colorado’s rules are passed this month, the sales minimums would kick in here for the 2027 model year and ramp up from there.
The rules the AQCC will debate and vote on also include a program to limit nitrogen oxide emissions from existing heavy trucks driven by fossil fuel engines. Nitrogen oxide is a key component of Front Range ozone, and the nine northern Front Range counties are in “severe” violation of EPA caps.
The “Low NOx” program would impact more than 28,000 heavy trucks beginning in the 2027 model year, growing to 44,000 engines by 2050. Over that time, the rules would affect a total of 722,000 vehicles on the road.

The AQCC plans to double down on cuts to emissions from lighter passenger cars as well, with work on a followup to existing electric vehicle requirements they are calling “Clean Cars 2.” Both the clean cars sequel and the advanced clean trucks measures may also be overtaken by recent big federal moves: The EPA on Wednesday proposed strict new vehicle emissions standards aiming for 67% of new passenger car sales to be electric by 2032.
The motor carriers want the AQCC to be more realistic about what’s happening on the roads in Colorado. Few electric-powered models of heavy trucks are for sale right now, and those available are both back ordered and extremely pricey, the motor carriers’ Fulton said. It’s not at all clear how many more truck builders will have models widely available for the 2027 model year, he said.
Moreover, a blanket clean trucks standard nationwide doesn’t account for acute regional differences, Fulton said. California’s large, regularly spaced cities and warmer weather allow for faster adoption of electric trucks that will at first have more limited operating range than diesel models. Cold weather affects battery storage capacity, as does hauling loads up Colorado’s steep mountain terrain.
Long-haul truckers will have to make major adaptations as well. Federal trucking safety rules limit how many hours in a row a driver can be on the road before taking extended rest. Hauling companies will have to build in electric charging time into schedules, and that’s assuming federal and state authorities help build enough heavy-duty fast charging stations to serve the industry, Fulton said. A trip to Colorado’s Western Slope that can now be done in one shift may have to be split over two shifts, upending the volatile economics of the trucking industry, he said.
“We’d be on the edge of the range to just get to Grand Junction today,” he said.
Fulton says the carriers would like the AQCC to consider expanding definitions of low-emission heavy trucks that would fit under a new standard. Current zero-emission technology is usually defined as electric motors powered by cleanly generated electricity, or emerging hydrogen technology. Truckers have had success, for example, with so-called renewable natural gas, which is methane captured from the decomposing trash in landfills.
Carriers would also like to see a greater emphasis on a trade-in program that would get older, dirtier diesel rigs off the road. Modern fossil fuel engines burn much more cleanly, and removing the highest-emitting engines could go a long way to clean Colorado skies, Fulton said.
“The difficulty I’m going to have on that one is nobody wants to replace a diesel with a diesel,” he said.
The EPA also adopted new heavy truck standards nationwide in December, but environmental advocates said the California model goes farther in reducing nitrogen oxide that contributes to Colorado’s ozone. They want the state to keep moving forward on adopting the California model.
The Colorado Energy Office and other state officials have thoroughly studied the heavy truck market’s capacity in the next few years, and they conclude that clean models will be widely enough available to the industry, said Cindy Copeland, air and climate policy advisor for Boulder County. Copeland is one of a group of Front Range elected officials and agencies in Colorado Communities for Climate Action, which has been pushing the AQCC to go farther, faster on controlling ozone and greenhouse gases.

The AQCC should reject the “market is not ready” claims about clean trucks, Copeland said.
“We heard this argument, the exact same one, when Colorado adopted zero-emissions passenger vehicle standards back in 2019,” said Copeland, noting that state consumers are adopting electric vehicles even faster than planned in that effort four years ago. “That’s the way the market is moving.”